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//
//   http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.doris.nereids.trees.plans.logical;

import org.apache.doris.nereids.memo.GroupExpression;
import org.apache.doris.nereids.properties.DataTrait;
import org.apache.doris.nereids.properties.LogicalProperties;
import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.trees.expressions.Slot;
import org.apache.doris.nereids.trees.plans.LimitPhase;
import org.apache.doris.nereids.trees.plans.Plan;
import org.apache.doris.nereids.trees.plans.PlanType;
import org.apache.doris.nereids.trees.plans.algebra.Limit;
import org.apache.doris.nereids.trees.plans.visitor.PlanVisitor;
import org.apache.doris.nereids.util.Utils;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;

import java.util.List;
import java.util.Objects;
import java.util.Optional;

/**
 * Logical limit plan
 * eg: select * from table limit 10
 * limit: 10
 * <p>
 * eg: select * from table order by a limit 100, 10
 * limit: 10
 * offset 100
 */
public class LogicalLimit<CHILD_TYPE extends Plan> extends LogicalUnary<CHILD_TYPE> implements Limit {
    private final LimitPhase phase;
    private final long limit;
    private final long offset;

    public LogicalLimit(long limit, long offset, LimitPhase phase, CHILD_TYPE child) {
        this(limit, offset, phase, Optional.empty(), Optional.empty(), child);
    }

    public LogicalLimit(long limit, long offset, LimitPhase phase, Optional<GroupExpression> groupExpression,
            Optional<LogicalProperties> logicalProperties, CHILD_TYPE child) {
        super(PlanType.LOGICAL_LIMIT, groupExpression, logicalProperties, child);
        this.limit = limit;
        this.offset = offset;
        this.phase = phase;
    }

    public LimitPhase getPhase() {
        return phase;
    }

    public boolean isSplit() {
        return phase != LimitPhase.ORIGIN;
    }

    public long getLimit() {
        return limit;
    }

    public long getOffset() {
        return offset;
    }

    @Override
    public List<Slot> computeOutput() {
        return child().getOutput();
    }

    @Override
    public String toString() {
        return Utils.toSqlStringSkipNull("LogicalLimit",
                "limit", limit,
                "offset", offset,
                "phase", phase,
                "stats", statistics
        );
    }

    @Override
    public String toDigest() {
        StringBuilder sb = new StringBuilder();
        sb.append(child().toDigest());
        sb.append(" LIMIT ? ");
        if (offset != 0) {
            sb.append(" OFFSET ?");
        }
        return sb.toString();
    }

    @Override
    public int hashCode() {
        return Objects.hash(limit, offset);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        LogicalLimit<?> that = (LogicalLimit<?>) o;
        return limit == that.limit && offset == that.offset && phase == that.phase;
    }

    @Override
    public <R, C> R accept(PlanVisitor<R, C> visitor, C context) {
        return visitor.visitLogicalLimit(this, context);
    }

    public List<? extends Expression> getExpressions() {
        return ImmutableList.of();
    }

    public LogicalLimit<Plan> withLimitChild(long limit, long offset, Plan child) {
        Preconditions.checkArgument(children.size() == 1,
                "LogicalTopN should have 1 child, but input is %s", children.size());
        return new LogicalLimit<>(limit, offset, phase, child);
    }

    @Override
    public Plan withGroupExpression(Optional<GroupExpression> groupExpression) {
        return new LogicalLimit<>(limit, offset, phase, groupExpression, Optional.of(getLogicalProperties()), child());
    }

    @Override
    public Plan withGroupExprLogicalPropChildren(Optional<GroupExpression> groupExpression,
            Optional<LogicalProperties> logicalProperties, List<Plan> children) {
        Preconditions.checkArgument(children.size() == 1);
        return new LogicalLimit<>(limit, offset, phase, groupExpression, logicalProperties, children.get(0));
    }

    @Override
    public LogicalLimit<Plan> withChildren(List<Plan> children) {
        Preconditions.checkArgument(children.size() == 1);
        return new LogicalLimit<>(limit, offset, phase, children.get(0));
    }

    @Override
    public void computeUnique(DataTrait.Builder builder) {
        if (getLimit() == 1) {
            getOutput().forEach(builder::addUniqueSlot);
        } else {
            builder.addUniqueSlot(child(0).getLogicalProperties().getTrait());
        }
    }

    @Override
    public void computeUniform(DataTrait.Builder builder) {
        if (getLimit() == 1) {
            getOutput().forEach(builder::addUniformSlot);
        } else {
            builder.addUniformSlot(child(0).getLogicalProperties().getTrait());
        }
    }

    @Override
    public void computeEqualSet(DataTrait.Builder builder) {
        builder.addEqualSet(child().getLogicalProperties().getTrait());
    }

    @Override
    public void computeFd(DataTrait.Builder builder) {
        builder.addFuncDepsDG(child().getLogicalProperties().getTrait());
    }
}
